Al-Y-Ni-B非晶質合金玻璃形成能力及結晶行為研究

The Glass Forming Ability and Crystallization Behavior of Al-Y-Ni-B Alloy

許名鋒(min-fung shu)

指導教授 ： 陳適範 ； 林於隆

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00274

摘要

本研究以Al87Y8Ni5非晶合金為基礎，添加15at.%的B元素提高其熱穩定性及非晶質形成能力，以單輥旋淬法製作非晶薄帶，實驗利用示差掃描熱分析儀(DSC)進行合金薄帶熱性質測定，並以恆溫與非恆溫方式量測合金活化能以及Avrami指數。其中，(Al87Y8Ni5)85B15非晶合金於升溫時產生玻璃轉換現象，玻璃轉換溫度(Tg)為529 K，過冷液態區(ΔTx)為24.6 K，其結晶活化能為228 kJ/mol，較Al87Y8Ni5非晶合金的159 kJ/mol具備更優秀的熱穩定性。Al87Y8Ni5非晶合金之Avrami指數n介於1.5~2.1之間，顯示其成核速率隨晶化時間而遞減，而(Al87Y8Ni5)85B15非晶合金Avrami指數n則介於2.3~3.1之間，成核速率隨晶化時間遞增，亦代表含硼合金之非晶穩定性較高。以上兩個非晶合金薄帶在經過不同溫度退火後，隨著B的添加，Al3Y及AlNi相的析出往高溫遞移，而合金薄帶之硬度則於593-598 K間進行晶化後，因析出奈米鋁顆粒獲得最高之硬度，Al87Y8Ni5及(Al87Y8Ni5)85B15薄帶分別可以達到566與575 Hv。

關鍵字

非晶質合金 ； Avrami指數 ； 硬度

並列摘要

In this study, 15 at.% of boron is added to increase amorphous forming ability of Al87Y8Ni5 alloy ribbons by single roller melt-spinning process. Thermal properties including crystallization activation energy and the Avrami exponent of crystallization are obtained by non-isothermal and isothermal analyses. The (Al87Y8Ni5)85B15 amorphous alloy ribbon demonstrates a glass transition temperature (Tg) at 529 K, and its ΔTx (=Tx-Tg) value is 24.6 K. Crystallization kinetic study show that the 15 at.% of boron increases the activation energy for crystallization from 159 to 228 kJ/mol. The Avrami exponent n value of Al87Y8Ni5 amorphous alloy is 1.5~2.1 indicating a decreasing nucleation rate with crystallization time, whereas the n value of (Al87Y8Ni5)85B15 amorphous alloy ribbon is 2.3~3.1 or the nucleation rate increases with time. The maximum hardness is obtained for both non-boron and boron added alloys after crystallization at 593-598 K due to formation of nano-crystallites. The highest hardness achieved is 566 and 575Hv for Al87Y8Ni5 and (Al87Y8Ni5)85B15 alloys, respectively. It is further found that the Al3Y and AlNi phases delay their precipitations till higher temperatures due to boron addition. The boron addition apparently improves the stability of Al87Y8Ni5 amorphous alloy.

並列關鍵字

Amorphous alloy ； Avrami exponent ； hardness

參考文獻

[3] K. R. Cardoso, A. Garcia Escorial, M. Lieblich, and W. J. Botta F, "Amorphous and nanostructured Al-Fe-Nd powders obtained by gas atomization," Materials Science and Engineering A, vol. 315, 2001, pp. 89-97.

[5] A. L. Greer, "Metallic glasses," Science , vol. 267, no. 5206, 1995, pp. 1947-1953.

[6] M. Gich, T. Gloriant, S. Surinach, A. L. Greer, and M. D. Baro, "Glass forming ability and crystallisation processes within the Al-Ni-Sm system," Journal of Non-Crystalline Solids, vol. 289, 2001, pp. 214-220.

[7] A. Inoue, T. Zhang and A. Takeuchi, "Ferrous and Nonferrous Bulk Amorphous Alloys," Materials Science Forum, vol. 269-272, 1998, pp. 855-864.

[9] W. Klement, R.H. Wilens and P. Duwez, "Non-crystalline Structure in Solidified Gold-Silicon Alloys," Nature, vol. 187, 1960, pp. 869-870.